This section provides background information related to the present disclosure which is not necessarily prior art.
This invention relates to bullets, and in particular to a hollow point bullets.
Hollow point bullets have a cavity at the front of the bullet which facilitates the expansion of the bullet after it impacts its target. However, a problem with at least some hollow point bullets is that with some materials, such as wall board, the bullets don't expand as intended, and thus the performance and penetration is unpredictable. For many users, including but not limited to law enforcement users, it is important that a bullet perform predictably and consistently, to avoid unintended consequence. In fact the FBI has developed a test protocol (as of 2014) that measures a bullet's performance in a variety of materials:
Test event 1—Bare Gelatin
Gelatin block 10 feet from muzzle
Test event 2—Heavy Clothing
Gelatin block covered with four layers of clothing 10 feet from muzzle.                Layer one—Sew Classic Knits T-shirt        Layer two—Symphony broad cloth—Dress Shirt        Layer three—Polartec Fleece 200        Layer four—14 oz Bull Denim        
Test event 3—Steel
Two pieces of 20 gauge cold rolled galvanized steel                Gel block is covered in one layer of cotton t-shirt and one layer of cotton shirt from above        Gel block is 18 inches behind the rear most piece of steel with the block 10 feet from muzzle.        
Test event 4-Wallboard Two square pieces each ½ inch thick gypsum wallboard set 3.5 inches apart. Gel block is covered in one layer of cotton t-shirt and one layer of cotton shirt.
Gel block is 18 inches behind the rear most piece of wall board with the block 10 feet from muzzle.
Test event 5—Plywood
One square piece of 23/32 sanded pine plywood                Gel block is covered in one layer of cotton t-shirt and one layer of cotton shirt.        Gel block is 18 inches behind the rear of plywood with the block 10 feet from muzzle.        
Test event 6—Auto Glass
One piece of A.S.I ¼ inch thick laminated safety glass measuring 15×18 inches.                Glass set at an angle of 45 degrees with the horizontal        Line of bore of barrel is offset 15 degrees to the side to imitate a compound angle of impact with the glass.        Gel block is covered in one layer of cotton t-shirt and one layer of cotton shirt.        Gel block is 18 inches behind the glass with the block 10 feet from muzzle.        